Breast milk can be pumped by human breast pumps, typically with flanges that are pressed to the breasts, as seen in FIG. 6A. In FIG. 6A, a flange 600 is in operable communication with a breast pump 602 that produces pressure intermittently, or cyclically in both the positive and negative aspects, as seen in FIG. 6B. Negative pressure, or vacuum, withdraws the milk, which falls through a tube 603 into a container 604. This process, commonly described as suck and release, is the underlying mechanical means of milk extraction employed by most conventional human breast pumps.
A different breast milk expression device is disclosed in U.S. Pat. No. 4,607,596, issued Aug. 26, 1986, to Whittlestone et al. As seen in FIG. 7A, the Whittlestone apparatus 700 has two breast cups 702, 704 which each have a liner 706, 708 respectively. Each liner creates a pulsation chamber 710 between the liner and the cup, and a vacuum chamber 712 inside the liner when a breast is placed in the cup.
A pump 714 provides vacuum through lines 716, 718 and pulsating pressure through lines 720, 722, to the inner and outer chambers 712, 710, respectively, as seen in FIG. 7B. The line 712V in FIG. 7B shows the generally constant vacuum at the breast in the chamber 712, and the line 710P shows the pulsation pressure in the chamber 710. Thus, the Whittlestone device is distinguished from the other devices by utilizing unidirectional negative pressure for primary milk extraction, in combination with a pressure chamber that utilizes alternating positive and negative pressure to actuate pulsation (liner wall movement, ISO 3918) to express milk in a manner both effective and comfortable for the user.
Suck and release breast pumps, along with their flanges, are owned by or available to many women, retail, rental and medical facilities. However, these pumps could not be used with the Whittlestone breast cup assemblies because the Whittlestone breast cup assemblies require two types of pneumatic power. Thus, there is a need for an adapting device that permits the suck and release pumps to actuate breast cup kits requiring dual sources of pressure.
Accordingly, an object of the present invention is to enable use of breast cup assemblies that utilize dual pressure sources, such as negative unidirectional pressure for vacuum to the breast, and bidirectional pressure for actuation of pulsation, in combination with single pressure output suck and release breast pumps.